Conventionally, an image playback device that plays back a 3D (three-dimensional) image using two parallax images is known. A method of playing back images stored mixedly including 3D images and 2D (plane) images in such an image playback device by separating the 3D images and the 2D images into different files is considered (for example, refer to Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2005-94145